Presentation Title

Efforts to Develop a Thiourea-Catalyzed Addition to ortho-Quinone Methides

Faculty Mentor

Raul Navarro

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 96

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Abstract

The transformation of aromatic building blocks into more structurally complex molecules provides a powerful means for accessing a number of chiral, value-added intermediates. Within this realm, dearomatization reactions that proceed via an ortho-quinone methide (oQM) intermediate serve as an efficient platform to build stereochemically rich organic intermediates. The goal of our studies is to develop a new catalytic platform for an enantioselective addition reaction to oQMs. This novel transformation will capitalize on the unique reactivity of thiourea catalysts, which have been previously shown to activate a number of Lewis basic electrophiles toward nucleophilic attack. Specifically, we anticipate that very simple β-halo phenol derivatives will undergo a thiourea-catalyzed addition with a number of carbon-based nucleophiles. We have successfully developed a concise and scalable protocol to access a quinone methide precursors and have established a reliable method to prepare several thiourea catalysts. Although initial attempts to promote an addition reaction have been unsuccessful, we will continue to screen a number of reaction parameters to facilitate the desired transformation. The successful implementation of this proposal will significantly improve upon currently existing methods to promote catalytic reactions of oQMs and will provide a new way to make complex organic compounds from simple starting materials.

Key Words: ortho-quinone methides, symmetric organic catalyst, thiourea, dearomatization reaction

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Efforts to Develop a Thiourea-Catalyzed Addition to ortho-Quinone Methides

CREVELING 96

Abstract

The transformation of aromatic building blocks into more structurally complex molecules provides a powerful means for accessing a number of chiral, value-added intermediates. Within this realm, dearomatization reactions that proceed via an ortho-quinone methide (oQM) intermediate serve as an efficient platform to build stereochemically rich organic intermediates. The goal of our studies is to develop a new catalytic platform for an enantioselective addition reaction to oQMs. This novel transformation will capitalize on the unique reactivity of thiourea catalysts, which have been previously shown to activate a number of Lewis basic electrophiles toward nucleophilic attack. Specifically, we anticipate that very simple β-halo phenol derivatives will undergo a thiourea-catalyzed addition with a number of carbon-based nucleophiles. We have successfully developed a concise and scalable protocol to access a quinone methide precursors and have established a reliable method to prepare several thiourea catalysts. Although initial attempts to promote an addition reaction have been unsuccessful, we will continue to screen a number of reaction parameters to facilitate the desired transformation. The successful implementation of this proposal will significantly improve upon currently existing methods to promote catalytic reactions of oQMs and will provide a new way to make complex organic compounds from simple starting materials.

Key Words: ortho-quinone methides, symmetric organic catalyst, thiourea, dearomatization reaction